This would be an interesting thing to monitor if you split it between categories, e.g:
(a) Delegations from Steem (+ Utopian) for account set up
(b) Delegations to voting bots (incl smartsteem, minnowbooster)
(c) Purchases of delegtions from minnowbooster, blocktrades etc
(d) Delegations to initiatives (curie etc).

Probably worth converting vests to SP as well - it's easier for most people to relate to.